| 摘要 |
PURPOSE:To provide a shock absorber which exhibits a soft spring function by variably adjusting the orifice opening area of a passage with the use of an output circuit pressure from a pump circuit which responds to a vibration exciting frequency applied to a damper body, as a pilot pressure. CONSTITUTION:The flow rate of oil fed from a pressure chamber 30 into a pilot chamber 40 is restricted suitably by a port 26. Further, owing to an accumulator effect given by a spool 13 which is urged by a spring 14 and a pressure in a reservoir chamber, a part of oil fed into the pilot chamber 40 is gradually returned to an oil chamber 9 through a restricted orifice 25. Further, the pressure of the pilot chamber 40 is directly determined in a steady-state condition by a feed flow rate of hydraulic oil from the pressure chamber 30 and a return flow rate of hydraulic oil flowing through the orifice 25, that is, the pressure is low in a low vibrating speed range in which the feed volume per unit time is small, but becomes higher in an intermediate vibrating speed range in which the vibrating speed increases. Further, a closed condition of a port 10a in a low frequency range and an opening area controlling condition thereof in an intermediate frequency range can be automatically selected and determined. |
